The Science Behind the Simulator

← Back to Simulator

🎯 The Vision

MatchSire was built with a simple goal: give horse breeders of every breed a scientifically accurate, visually stunning tool to predict breeding outcomes. No guesswork, no oversimplified charts — real Mendelian genetics rendered beautifully in your browser.

Whether you're breeding Standardbreds, Quarter Horses, Thoroughbreds, Paints, Arabians, Warmbloods, or Appaloosas — MatchSire models the genetics that matter for your breed.

Whether you're a professional breeder planning your next season or a fan exploring genetics, MatchSire makes complex inheritance patterns accessible and interactive.

🧬 The Genetics

MatchSire models real equine genetics using established research on equine coat color, gait, dilution genes, and disease inheritance across all major breeds:

Gene	Locus	Function	Alleles
Extension	MC1R	Controls black pigment production	E (black possible) / e (red only)
Agouti	ASIP	Distributes black pigment	A (bay — restricts black) / a (uniform black)
Grey	STX17	Progressive depigmentation	G (greying) / g (non-grey)
Roan	KIT region	Even mix of white hairs	Rn (roan) / rn (non-roan)
Cream	SLC45A2	Dilution — palomino, buckskin, cremello, perlino	Cr (dilute) / N (non-dilute)
Dun	TBX3	Dilution + primitive markings (dorsal stripe)	D (dun) / d (non-dun)
Gait	DMRT3	Gait coordination pattern (Standardbred, gaited breeds)	C (trot tendency) / A (pace tendency)

🎲 The Math — Monte Carlo Simulation

Rather than showing simple Punnett square percentages, MatchSire runs 10,000 Monte Carlo simulations for each breeding pair. This approach:

• Handles multi-gene interactions that simple cross tables can't capture
• Incorporates breed-specific population frequencies for unknown genotypes based on published research
• Produces statistically robust probability distributions
• Accounts for complex phenotype determination (e.g., grey epistasis over base color)

🛡️ Disease Screening

MatchSire tracks genetic diseases relevant to each breed, including:

• GBED — Glycogen Branching Enzyme Deficiency (QH, Paint, Standardbred)
• HYPP — Hyperkalemic Periodic Paralysis (QH, Paint, Appaloosa)
• HERDA — Hereditary Equine Regional Dermal Asthenia (QH, Paint)
• OLWS — Overo Lethal White Syndrome (Paint, QH, Standardbred)
• PSSM1 — Polysaccharide Storage Myopathy (QH, Paint, Warmblood, Draft)
• MH — Malignant Hyperthermia (QH, Paint)

Breed-specific panels show automatically when you select your breed in the simulator. Future updates will add SCID/CA/LFS (Arabian), WFFS (Warmblood), JEB (Draft), and CSNB (Appaloosa).

The compatibility score factors disease risk heavily — breeding two carriers of the same recessive disease significantly lowers the score.

🐴 Standing Stallions

MatchSire is proudly part of the Standing Stallions family. Originally built for Standardbred breeders, MatchSire now serves every major breed — Quarter Horse, Thoroughbred, Paint, Arabian, Warmblood, and Appaloosa. Visit our main site for stallion listings, breeding information, and industry news.